The S30 was a once-and-only frame. There is only one S30. The other white frame is the Silvio, that was retrospectively named (kind of by accident) the "Silvio S30" much after the actual S30 was built. It was only the "Silvio" prior to this. The S30 replaced what was the Silvio. But those older models are NOT actual S30 - they are not the same. So there is no "Silvio S30." I know this because I was there when they were welded.
The bike batch previous to the actual S30 was the Silvio only - the name "S30" was never discussed or even invented until that model was well into production 18 months or so after the last batch of
Silvio's were made and already selling.
The "S30" name was meant to be a complete change from "Silvio" in order to completely delineate it as its own model - with a more solid front end and unique graphic that only said "S30" on the side. The "Silvio" name was intended to be 100% abandoned at that point. It was our first model where we decided to get away from the names like Silvio and Vendetta to more "numbers" for the models (S30 and then V20, then S40). But at some point there was an article that said "Silvio S30" and it embedded like a lone star tick and here we are.... the misinformation machine is real.
The older welded frame Silvio was actually much closer to the modern S40 as far as seat angle goes. Then over time the hydroformed Silvio morphed a bit and kind of became something else.
Main differences:
S30 - No front suspension fork and very slightly altered geometry as a result (because the front suspension fork did not work as intended always - even on the older models - the previous white Silvio just before the S30 did have a suspension front end)
S30 - Triangular hole in the rear gusset (Silvio had a round hole in the same place)
S30 - Unique paint job that had "S30" graphic and the new "Z" logo on the hydroformed tube
S30 - Different rear and triangle that had a slightly altered rear elastomer position and angle
Those are the biggies that allow one to tell at 25 feet looking at the bikes which one is which. I have seen repainted S30's that are sold as "Silvio" incorrectly - the triangular hole is the main giveaway in that case.
The S30 was sadly not as fast as the V20 and also not as competent a climber as the then-being-prototyped-by-me handmade S40. The S40 handbuilt prototype was tested against the production S30 for nearly 13 months before its reveal and decision to produce the new S40 as opposed to another batch of S30's. The S40 just made more sense and was different enough from the V20 to stand out as its own machine with its own purpose and abilities that we did not have a good model for at the time. The S30 just was too much a gray zone. And the rear end was not at all suitable to attaching racks or carrying anything, and there were no mounts on the frame for anything like that. Heavy bags draped over the seat would cause the rear suspension to have too much lateral feel in my opinion so to me that was a negative and why the S40 hs a solid rear end.
In our side-by-side testing of the different models, I likened the S30 to the "wannabe racer" that would always lose to the V20 in any race or rolling hill riding, and the S40 was the ultimate workhorse machine that did all the stuff the V20 and S30 was not intended to do - like carry 4 panniers plus a trunk bag like a champion of the touring world.
And when it comes to production/warehousing/etc. we can only have so many models at one time and also only can make them one at a time (especially the hydroformed models) so at that time the S40 was the winner and for marketing/sales it is easier to differentiate and reduce the infamous decision paralysis of having too many models that are too close together in purpose and appearance.
If you score an S30 it is a great bike - don't get me wrong - it fits the middle zone between the two bikes: Not as fast as the V20 in a flat out race, but it does climb better than the V20 on a sustained climbing challenge for most riders. But, it cannot tour or as easily do the clydesdale hauling that the S40 was designed for and the S40 will pull away from the S30 in the same climbing challenge every time....